Redshift data and spectra from the first 100,000 galaxies measured by
the 2dF (Two-degree Field) Galaxy Redshift Survey will be released to
the world astronomical community on June 30. Thirty-two researchers from
13 institutions (listed below) have been carrying out the survey with
the Anglo-Australian Telescope near Coonabarabran in eastern Australia.
They have now netted more than 175,000 redshifts and will reach the
survey target of 250,000 by the end of 2001. Redshift data can be
converted to positions in space and so the survey has created the most
comprehensive three-dimensional map of the local Universe yet made.

As well as providing by far the largest available set of galaxy
spectra for mapping the Universe, the 2dFGRS database is a goldmine of
interesting and unusual objects.

"The 2dF dataset is a free gift of 100,000 redshifts to astronomers
world-wide. They can apply it immediately to improving our understanding
of galaxy evolution and the structure of the Universe," said 2dF survey
team co-leader Dr Matthew Colless of the Australian National University.

"For many rare types of objects, we need to have large samples before
we can understand the objects' properties and how they are related to
their environments," he said.

"For instance, radio telescopes are extremely good at detecting
extremely powerful, 'active' galaxies in the very distant universe. But
to understand how these galaxies evolve over time, we need also a large
sample of such galaxies nearby. This can only be achieved with an
optical telescope," Dr Colless said. "Cross-matching the 2dF survey data
with large-area radio surveys will give a sample of up to 4,000
radio-emitting galaxies in the local Universe."

A key finding from the data, posted at
http://arXiv.org/abs/astro-ph/0105252 on May 15, is the first firm
evidence that the irregularities in the cosmic microwave background are
still imprinted on the distribution of galaxies in today's Universe. The
large sample of galaxies generated by the 2dF survey allowed the
researchers to measure the characteristics of the galaxy distribution
with very small random errors. "These subtle over-densities in the
galaxy distribution range in size from about 300 million to 1.5 billion
light-years," said team co-leader Prof. John Peacock of the University
of Edinburgh.

The same study also found that 'normal' (baryonic) matter makes up
only 15% of the Universe's total matter - the rest being the
unidentified 'dark matter'. And total matter is only 35% of the
Universe's contents, according to another 2dF finding in 'Nature' on
March 8. (The rest is believed to be 'dark energy'.)

The 2dF dataset will also be used to test theories of cosmological
inflation, the extremely rapid growth of the Universe just after the Big
Bang.

Designed and built by the Anglo-Australian Observatory, the 2dF is
one of the world's most complex astronomical instruments, able to
capture 400 spectra simultaneously. A robot arm positions up to 400
optical fibres on a field plate, each to within an accuracy of 20
micrometres. Light from up to 400 objects is collected and fed into two
spectrographs for analysis. The expansion of the Universe shifts galaxy
spectra to longer wavelengths. By measuring this 'redshift' in a
galaxy's spectrum, the galaxy's distance can be determined.

The 2dF survey covers a total area of about 2,000 square degrees,
selected from both northern and southern skies.

ACKNOWLEDGEMENT
The 2dF Galaxy Redshift Survey has been made possible by the dedicated
efforts of the staff of the Anglo-Australian Observatory, both in
creating the 2dF instrument and in supporting it on the telescope.